Wireless communication systems deliver a wide variety of communication services to mobile users separated and/or moving from the fixed telecommunications infrastructure. These wireless systems employ radio techniques to interconnect mobile user devices with various base stations in a wireless communication network, often in a cellular geometry. The base stations, in turn, are connected to mobile switching centers which route connections to and from the mobile user devices to other users on different communications networks such as the public switched telephony network (PSTN), Internet, etc. In this manner, users that are away from fixed sites or are on the move may receive various communication services such as voice telephony, paging, messaging, email, data transfers, video, Web browsing, etc.
Since radio frequencies are employed for the base station-mobile user wireless interconnection, all wireless users must agree on a common set of protocols to share the scarce radio spectrum allocated for wireless communication services. One important protocol relates to the access method used to connect a mobile user device to the wireless communications network. Various access methods include frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and orthogonal frequency division multiplex (OFDM). OFDM utilizes a plurality of carriers spaced apart in the frequency domain such that data modulated on each carrier is orthogonal to the others.
One popular wireless communication protocol suite is known as Universal Mobile Telecommunications System (UMTS). UMTS is an evolving third generation wireless communication system with ongoing upgrades, documented in a series of protocol releases. For example, Release 1999 (R99) established the basic circuit switched and packet switched network services for UMTS. Subsequent releases, such as Rel-4, Rel-5, Rel-6, Rel-7, Rel-8, etc. have enhanced the capabilities of UMTS in many aspects, for example, increased data rates, improved Internet Protocol (IP) access, higher order modulation, multiple input multiple output (MIMO) transmission, etc.